T5B/C airside to T3 landside on a Wednesday morning - quickest route (using e-gates)?
 

This is primarily aimed at @corporate-wage-slave for his unrivalled knowledge, but all contributions welcome...

My dad is arriving from EWR at T5 B/C at 09.30 on Weds and needs to get to the post office at T3 landside. Travelling HBO, British e-passport.

Is it likely to be quicker to take the connections bus from T5B and go through passport control using e-gates at T3, or can queues there be long mid-morning so T5 better?

I suppose I could advise him to go to T5A and see if the queue is very long, if it is go through connections and take the bus from there. Thoughts?

Thanks!

Personally I would indeed take the Flight Connection bus direct from T5B to T3 and then - once in T3 - follow the sign for arrivals / baggage reclaim rather than T3 Flight Connections security. Flight Connections T3 has moved to a new location, but you can still access the UK Border from a bus arrival. The trickiest bit is once landside - he needs to go rightwards, through some corridors to the check-in area, then up one level to the Post Office, which is nearly opposite T3 Fast Track. T3 arrivals is actually in a separate building to the rest of T3 and the link is via those corridors.

The alternative is probably best to go out of T5 in the usual way then HEX from T5 to T3, HEX T3 is a bit nearer T3 than the Underground.

Based on advice I received from this board, I did exactly this a couple of weeks ago. Arrived at T5C, chose to walk to T5B rather than take the train, and then hopped on the airside bus to T3. Once at T3, it was easy to follow the Arrivals sign to backtrack to immigration and to go landside.

From the T3 customs exit into the landside arrivals area look far right to the Caffè Nero and go between Caffè Nero and the lifts, through the passage way there to T3 departures. Do not go up or down any stair or escalator until you see some airline checkin counters, indicating you are in the departures building. Then go upstairs (any stair will do) and find the Fast Track entrance. Stand there and look around and the Post Office is visible, almost behind you as you face the Fast Track entrance (as c-w-s says).